A movie about a man who seeks vigilante justice after a family member is harmed, directed by the Generation Y auteur who made “Saw,” sounds like it is bound to be garish and exploitative. You can almost hear the heavy metal soundtrack and feel the headache induced by the MTV-style editing.

“Death Sentence” is a surprise, then, and not just because it’s kind of good. It’s generally a calm, quiet film, with no flashy cuts or perverse camera angles. It depicts violence realistically in that the characters actually suffer from their injuries, but it’s not fetishistic about it.

Also, it stars Kevin Bacon. Bacon’s films are not all good, of course, but he is nearly always good in them. In “Death Sentence,” he takes his role as family-man-turned-killer Nick Hume seriously, treating it with as much gravity as he would a role in a more prestigious movie. If the actors aren’t taking the movie seriously, the audience won’t either, and for the most part, “Death Sentence” depends on our believing that its events are plausible and its characters are motivated the way real humans are. Bacon’s performance ensures that even at its most bombastic, the film remains grounded in truth.

Nick starts out as a bean-counting white-collar type with a wife (Kelly Preston) and two sons. The older, Brendan (Stuart Lafferty), is a hockey star thinking about colleges. The younger, 14-year-old Lucas (Jordan Garrett), lives in Brendan’s shadow. The family is happy and typical.

Violence invades when a ghetto punk trying to earn his gang stripes randomly targets one of the Humes. Grief-stricken and failed by the justice system, Nick follows the culprit home with the intention of — what? He doesn’t know. He has a vague revenge plan in mind, but he’s not totally committed to it. Normal people do not automatically become cold-blooded killers, no matter how angry or sad they are. When Nick makes the transformation — faster than he intended, and maybe against his wishes altogether — he is horrified.

And it’s not over that easily, either. You kill one gang member, you get a whole nest of them chasing after you. Soon it’s war between Nick and the group, led by Billy Darley (Garrett Hedlund), a beefy white-trash thug who sells drugs part-time for a gun trafficker and all-around criminal named Bones (John Goodman). While the war escalates, with Nick’s remaining family members now in jeopardy, he tries to maintain his life, showing up at the office with bandages and bruises, and feigning surprise when a police detective (Aisha Tyler) tells him the creep who attacked his son was found stabbed to death.

The screenplay is based on Brian Garfield’s novel, which was a sequel to “Death Wish.” As adapted by Ian Mackenzie Jeffers, the story bears little resemblance to Garfield’s, and it’s hampered occasionally by clunky dialogue and morbidly funny foreshadowing, as when an exasperated Nick tells his arguing sons in an early scene, “Can’t we all just be civilized before I kill someone?”

The film is not done any favors by John Goodman, either, who on the one hand is always entertaining to watch, but who on the other hand is doing an unidentifiable accent that gets more laughs than it should.

But the movie is stabilized by Bacon’s believable performance and by James Wan’s confident direction. Though his “Saw” spawned a series that has earned some derision, and though his second film “Dead Silence” was dumped into theaters earlier this year and practically ignored, Wan is far more capable than his reputation would suggest. He accomplishes some very impressive technical feats in “Death Sentence,” including a lengthy one-take scene covering several levels of a parking garage, and he clearly knows his film history. “Dead Silence,” about a malevolent ventriloquist’s dummy, was an amusing homage to the cheesy matinee thrillers of yesteryear, and “Death Sentence” culminates in a highly accurate re-creation of “Taxi Driver.”

It’s at about the 80-minute mark that “Death Sentence” breaks free of its restraints and becomes the ultra-violent grindhouse flick you were expecting all along. (I believe the actual tipping point is when Nick suddenly speaks Spanish to a recalcitrant bartender before forcibly extracting information from him.) The movie isn’t as good then as it was before, when it was more thoughtful and suspenseful; the last act is mostly just people shooting at each other in the usual ways.

But it held my interest all the way through, and Bacon’s performance really is compelling. It would be unfair to dismiss this, as some have, as nothing more than a trashy revenge thriller by a former director of torture-horror. Wan is still growing, but he knows his stuff. I think he’s on the right track.

B-
(1 hr., 50 min.;
R, a lot of harsh profanity, a lot of strong violence, some of it fairly graphic.)